单选题 He tried very hard to ______ the authorities of his capabilities and loyalty, only to find that the more he tried, the less they believed him.
A. tell B. show
C. convince D. encourage

【正确答案】 C
【答案解析】[解析] 近义/同义辨析
A．tell告诉，表明；B．show显示，展出，引导；C．convince使确信，使信服； D．encourage鼓励。此句表示他努力要使有关当局/方面相信他的能力与忠诚，所以仅仅“告知”、“显示”是不够的，选项D不合句意，因此答案为C。